44 lines
1.3 KiB
C
44 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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#include <linux/bitmap.h>
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#include <linux/math.h>
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#include <linux/minmax.h>
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/*
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* Common helper for find_next_bit() function family
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* @FETCH: The expression that fetches and pre-processes each word of bitmap(s)
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* @MUNGE: The expression that post-processes a word containing found bit (may be empty)
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* @size: The bitmap size in bits
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* @start: The bitnumber to start searching at
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*/
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#define FIND_NEXT_BIT(FETCH, MUNGE, size, start) \
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({ \
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unsigned long mask, idx, tmp, sz = (size), __start = (start); \
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\
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if (unlikely(__start >= sz)) \
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goto out; \
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\
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mask = MUNGE(BITMAP_FIRST_WORD_MASK(__start)); \
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idx = __start / BITS_PER_LONG; \
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\
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for (tmp = (FETCH) & mask; !tmp; tmp = (FETCH)) { \
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if ((idx + 1) * BITS_PER_LONG >= sz) \
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goto out; \
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idx++; \
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} \
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\
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sz = min(idx * BITS_PER_LONG + __ffs(MUNGE(tmp)), sz); \
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out: \
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sz; \
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})
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unsigned long _find_next_bit(const unsigned long *addr, unsigned long nbits, unsigned long start)
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{
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return FIND_NEXT_BIT(addr[idx], /* nop */, nbits, start);
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}
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unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits,
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unsigned long start)
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{
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return FIND_NEXT_BIT(~addr[idx], /* nop */, nbits, start);
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}
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